Electrolyzers convert abundant chemicals into more valuable ones by the passage of electricity, normally by breaking down compounds into elements or simpler products. A proton exchange membrane based water electrolyzer (or PEM-based water electrolyzer) is a system in which water is oxidized at an oxygen electrode, or cell anode, to produce oxygen gas, releasing hydrogen ions, or protons, and electrons. The hydrogen ions migrate through a solid polymer electrolyte from the cell anode to the cell cathode, or hydrogen electrode, under the effect of the electric field imposed across the cell, while the electrons are transferred to the cathode by a direct current (DC) power source. The protons and electrons recombine at the cell cathode to produce hydrogen. Oxygen and hydrogen are generated in a stoichiometric ratio—two volume units of hydrogen for every one of oxygen—at a rate proportional to the applied cell current. A high pressure water electrolyzer may generate hydrogen and oxygen gas at pressures sufficient for storage (up to or exceeding 10,000 pounds per square inch) without the need for mechanical compression.